Dumb fuel question

[colVR4]

I can already hear the chuckles about the dumb question that I am going to ask but...what the hell!!

There has been a lot of talk about Optimax and BP Super being 97/98 RON, but it is hard to find Shell and BP garages near where I live. I have noticed that 4 Star LRP is also 97 RON. Can an unleaded car with a catalytic converter run LRP without it damaging the cat? I thought that LRP no longer had lead in it, so is it safe?

:INSERT INTO post VALUES ( I await the ridicule...

I am not worthy :bow:

[pjjohnson]

I asked the same question, face to face with someone who should know and they pulled a face, sneered and said never do it - I daren't ask whether it was the CAT or the engine that would suffer.

Better just to use PUL, but its not just BP and Shell that have SUL, Esso and TOTAL have it as well.

[colVR4]

Thanks,

Looking around on the internet it seems that the consensus is don't use LRP. I shall have to keep my eyes open for an Esso or Total garage as well.

I am not sure that the extra £2 per tank is worth it anyway. Has anybody actually noticed any difference in performance between the PUL and SUL? I think I may have seen a thread on the subject already but I can't remember where it was :Ponder:

I suppose I will just have to put my hand in my pocket and buy some mods if I want some decent performance increases.

:D

[Roadrunner]

It's not a stupid question :) No, you can't use LRP in an engine that's designed to use unleaded - you'll ruin the catalyst, very expensive to fix. There's also some well-documented stuff about it knackering turbos due to additives in the exhaust stream sticking to the turbine wheels and causing hot corrosion INSERT INTO post VALUES (sulphidation) leading to the early demise of the turbo. LRP never got a British Standard and the UK Gov is phasing it out altogether.

Any Super Unleaded petrol will be a reasonable alternative to Optimax or BP Ultimate - Esso and Texaco do SUL, not sure if any others do. SUL is rated at 97RON INSERT INTO post VALUES (as is Optimax and Ultimate btw!) but Shell claim a minimum 98.3 to 98.6 RON and, if the grapevine is to be believed, Ultimate has been touted as being up to 100 RON. Strange, though, that you'll not find anyone from BP to confirm or deny that claim ;)

Brian

[adam_shaw]

I'm in Germany at the moment, and the local Shell have a version of Optimax INSERT INTO post VALUES (is that the right one?) which they advertise as 100 Octane.

Gonna bring the car over with me next time, so shall have to try a tank, my filler flap says 95+ so its my duty to check out the '+' part.

[Kieran]

Originally posted by pjjohnson
I asked the same question, face to face with someone who should know and they pulled a face, sneered and said never do it - I daren't ask whether it was the CAT or the engine that would suffer.

Better just to use PUL, but its not just BP and Shell that have SUL, Esso and TOTAL have it as well.

If I remember correctly, LRP uses potassium/magnesium compounds to make up for the lack of lead. These two metals are less poisonous than lead, hence why they're used, but also do not have the same lubrication properties when in suspension in petrol, hence why not all older cars will run on LRP without suffering from VSR.
When these compounds are burnt in the engine, they pass out into the INSERT INTO post VALUES (red hot) catalytic converter, and chemically bond to the noble metals contained within the cat's honecomb structure. When these metals are coated, they no longer convert the nasty fumes into less noxious substances, and it'll screw you come emissions testing.

The other side effect is that as these noble metals get coated, the honeycomb structure becomes blocked, effectively suffocating your engine over time.... it begins with lower power/high fuel consumption and progresses from there...

In a nutshell.... Stay with unleaded!!